High ZS but R1+R2 and Ze ok

[timo]

Just extended a ring to include 4 more sockets.

Arangement =T-N-C-S
ZE of .27 and R1 + R2 of the ring is .67 ohms max

So by calc Zs should be .94 ohms. Im getting 1.3 ohms on zs test at sockets. anything from 0.7 to 1.3 ohms around the ring.

 

[GT1]

Are you getting the higher readings on old sockets or new or both ?

The ones with the higher readings may be wear and tear issues or poor connections generally.

May be beneficial to remove the socket plate and test off the bare conductor ends alone, to rule out the socket plate itself. !

I'm assuming your are using a "socket and see" type adapter at the socket with your meter ? Do the readings change if you wiggle it in the socket ?

 

[timo]

Thanks for the reply GT. The readings are on both old and new. The sockets were re-wired when the house was done up a few years ago i think. (all brown and blue) the existing is the same, some are .7 and some are 1.1 to 1.3. The new ones are 1.3 to all.

If there was a lose socket from etc wouldnt the R1 + R2 get this ? all the readings from the R1+R2 and L-N crossed on test were fine and max was .67 ohms and all within .05 ohms of each other.

 

[pevvers]

Have you got an RCD on the board? Sometimes they can put anything up to half an ohm on the circuit. If so, measure the impedance both sides of the RCD at the board and see if you get a difference. Also, if you've got a non trip loop test, they can sometimes give spurious ( )readings due to the low currents used....

 

[topquark]

I would also double check that they are all on the ring, with those readings it sounds as if there may be a spur there as well.

 

[timo]

thanks for the heads up on the RCD and Testers. And YES to both. 30MA on sockets and my tester is the easitest with the Trip Lock function thats allows me to check when RCDs in circuit.

The sockets with high readings are part of the ring and not spurs checked that one too

 

[greeny]

What type of instrument are you using for measuring the Zs.

 

[timo]

EasiTest

 

[greeny]

Sorry I had not read the previous thread.
I have a metrel easitest and do not trust it on trip lock zs readings
You are allowed to add your measured Ze to the R1+R2 established on the cold ring checks checks...see IEE guidance notes. Inspection and testing,
Greeny

 

[oldtimer]

Just to eliminate a problem with your tester lead or the actual socket change the lead on the tester to the 3 lead kit then unscrew the socket and test it at the terminals me thinks you will find you may get a differant reading .

 

[greeny]

The leads can be a problem with easitest, check their continuity and resolder, if dry joints.

 

[timo]

Just to eliminate a problem with your tester lead or the actual socket change the lead on the tester to the 3 lead kit then unscrew the socket and test it at the terminals me thinks you will find you may get a differant reading .

Will try this one. Thanks

 

[chris gray]

personally id do an r1 + r2 at all the sockets on the 'ring', think you may get a suprise

 

[pevvers]

personally id do an r1 + r2 at all the sockets on the 'ring', think you may get a suprise

The OP actually said that he's already done that in the first post, and reiterated that a few posts later, including cross connection of line and neutral too.

It sounds like he knows how to test a ring.

 

[scotsparky]

just out of curiosity what the L1-L2 +E1+E2 reading?